The present invention refers in one particular embodiment to localized, resource-block-based transmission on the downlink shared channel of an enhanced UMTS Radio Access Network (E-UTRA). Localized transmission implies that the shared-channel transmission to a certain UE is confined to a set of (physical) resource blocks, where each resource block consists of a certain number LRB of consecutive sub-carriers during one sub frame. The specific set of resource blocks to be used for transmission to a certain UE is selected by the Node B, e.g., based on knowledge of the downlink channel conditions (i.e. channel-dependent scheduling).
Channel-dependent scheduling provides a very efficient means to combat frequency-selective fading on the radio channel by simply dynamically avoiding parts of the spectrum that are subject to momentary deep fades. However, in some cases, channel-dependent scheduling is, for different reasons, not possible or not attractive. One reason can be that data may be targeting more than one UE, in which case there is not one single channel on which the channel-dependent scheduling can be based. Another reason might be that the channel may vary so fast in time, e.g. due to high mobility, that tracking of the instantaneous channel conditions is not possible. Yet another considerable reason might be that the downlink and/or uplink signaling overhead that is associated with channel-dependent scheduling is too “expensive”. This could be the case, e.g., for small payloads such as for voice services. If channel-dependent scheduling cannot be used, an exploitation of frequency diversity may be important in order to achieve good link performance.
In the case of localized transmission, frequency diversity can be achieved by simply transmitting on a set of resource blocks that are sufficiently spread in the frequency domain.